The inventor has observed that chemical vapor deposition (CVD) of cobalt can be used as a metal deposition technique for applications such as forming metal interconnects in an integrated circuit. CVD cobalt may be deposited within an opening, such as a via or trench, in thin layers and then annealed at about 250 to about 450 degrees Celsius to drive out impurities such as carbon, hydrogen, and oxygen. The deposition and anneal steps may be repeated several times to fill the opening with cobalt. However, conventional CVD chambers may not have anneal capabilities, requiring the substrates to leave the deposition chamber to be annealed and then returned to the CVD chamber for the additional deposition. Thus, the several deposition and anneal steps performed before the opening is filled with cobalt would take a lengthy period of time, resulting in low throughput and high expense for the process.
Thus, the inventor has provided improved methods and apparatus for depositing a cobalt layer in features formed on a substrate.